A flaw was found in QEMU. The VAPIC setup hypercall in hw/i386/vapic.c does not validate that the writable RAM alias remains within the option ROM window. A privileged guest user on a Q35/KVM machine can position this alias over locked SMRAM, bypassing chipset D_LCK protection and injecting code into System Management Mode memory.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-3241 advisory.

    hw/usb/hcd-xhci: Set reentrancy guard in timer functions (CVE-2026-17588)

    NOTE: Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/1f24066fc88d33455ee54a20f29994d9e69997ba     (v11.1.0-rc3)NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/5fbd2fe1cc54259d045d00d4966aa2db1ba990d6 (v11.0.4) (CVE-2026-18054)

    NOTE: https://gitlab.com/qemu-project/qemu/-/work_items/3917NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/0be94d8d9c28e6b7235b34133d057090fe93be6c (v11.1.0-rc2)NOTE: Fixed by:
    https://gitlab.com/qemu-project/qemu/-/commit/88a0e5e45b41d407cf9adf1f2cf6f20f394a578d (v11.0.4)     (CVE-2026-50624)

    NOTE: Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/733a98a552e4bd68932de1f58bd6ea39b57b261c     (v11.1.0-rc2)NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/6680c5612401c1eaa49eba134d14d374fefeb9d4 (v11.0.4) (CVE-2026-61402)

    NOTE: https://gitlab.com/qemu-project/qemu/-/work_items/3875NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/f404bf0e6504e0412a00ea64708f17d2a5e3f869 (v11.1.0-rc2)NOTE: Fixed by:
    https://gitlab.com/qemu-project/qemu/-/commit/a4abe1f1fa6f465b64fb400bea14c72bd5e32ac9 (v11.0.4)     (CVE-2026-61476)

    NOTE: Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/b9d248dfaca5e31377ea4f7204aae788a050bafd     (v11.1.0-rc2)NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/82520d7759557062a5fae2211e3c79bbd5f01ed3 (v11.0.4) (CVE-2026-63110)

    Host-side AddressSanitizer heap-buffer-overflow READ in current QEMU master through the virtio-net-pci     receive filtering path on q35. The crash is in receive_filter(). (CVE-2026-63320)

    NOTE: Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/a6e0519ea8ed6fc84fab9bf9ca82c7a55780f880     (v11.1.0-rc2)NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/52c7bb369b23dfcafb6e6d90665c777797b55e88 (v11.1.0-rc2)NOTE: Fixed by:
    https://gitlab.com/qemu-project/qemu/-/commit/f348425fddae38e0c1d6823501890acfb2a3bfb1 (v11.0.4)NOTE:
    Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/9a06bb17256c0a38f0b53025bf804d2e2035f93f (v11.0.4)     (CVE-2026-63321)

    NOTE: https://gitlab.com/qemu-project/qemu/-/work_items/3607NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/4727cc883b7e81d2c30b9801af54482d65b84292 (v11.1.0-rc2)NOTE: Fixed by:
    https://gitlab.com/qemu-project/qemu/-/commit/95b9a1bf26fef7c44f4925f78ade7fa824ed5e76 (v11.0.4)     (CVE-2026-63322)

    virtio-balloon: fix free-page BH teardown on unrealize (CVE-2026-66899)

    hw/net/virtio-net: strip trailing padding when caching RSC segment (CVE-2026-66900)

    hw/display/vga: fix text-mode OOB write after a graphics surface switch (CVE-2026-77913)

    A flaw was found in QEMU. The VAPIC setup hypercall in hw/i386/vapic.c does not validate that the writable     RAM alias remains within the option ROM window. A privileged guest user on a Q35/KVM machine can position     this alias over locked SMRAM, bypassing chipset D_LCK protection and injecting code into System Management     Mode memory. (CVE-2026-81627)

    io/channel-socket: do not treat a zero length write as an error (CVE-2026-84788)

    A use-after-free vulnerability was found in QEMU's 9pfs subsystem. A race condition between the main     thread and a worker thread when processing concurrent Tlcreate and Twalk requests allows a malicious guest     user to craft a fid path containing stale heap data, bypassing directory traversal restrictions and     escaping the shared directory boundary. This can lead to arbitrary host file read/write and code execution     (VM escape) as the QEMU process user. (CVE-2026-93834)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The version of qemu installed on the remote host is prior to 3.1.0-8. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-4009 advisory.

    NOTE: Fixed by: https://gitlab.com/qemu-project/qemu/-/commit/1f24066fc88d33455ee54a20f29994d9e69997ba     (v11.1.0-rc3)NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/5fbd2fe1cc54259d045d00d4966aa2db1ba990d6 (v11.0.4) (CVE-2026-18054)

    NOTE: https://gitlab.com/qemu-project/qemu/-/work_items/3917NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/0be94d8d9c28e6b7235b34133d057090fe93be6c (v11.1.0-rc2)NOTE: Fixed by:
    https://gitlab.com/qemu-project/qemu/-/commit/88a0e5e45b41d407cf9adf1f2cf6f20f394a578d (v11.0.4)     (CVE-2026-50624)

    NOTE: https://gitlab.com/qemu-project/qemu/-/work_items/3875NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/f404bf0e6504e0412a00ea64708f17d2a5e3f869 (v11.1.0-rc2)NOTE: Fixed by:
    https://gitlab.com/qemu-project/qemu/-/commit/a4abe1f1fa6f465b64fb400bea14c72bd5e32ac9 (v11.0.4)     (CVE-2026-61476)

    QEMU's 9pfs readonly check at line 2108-2109 tests mode & O_TRUNC and mode & O_APPEND against the raw 9P     open mode byte. For the 9P2000.u protocol, mode uses 9P flag values (Otrunc=0x10, Oappend=0x80), but the     check compares against Linux constants (O_TRUNC=0x200, O_APPEND=0x400). Since 0x10 & 0x200 = 0 and 0x80 &     0x400 = 0, both flags bypass the readonly guard. The mode is then correctly converted to host flags via     omode_to_uflags(), so open() is called with O_TRUNC -- truncating host files on readonly shares.9P2000.L     is NOT affected (guest passes Linux flags directly, so the bit values match). (CVE-2026-63318)

    Host-side AddressSanitizer heap-buffer-overflow READ in current QEMU master through the virtio-net-pci     receive filtering path on q35. The crash is in receive_filter(). (CVE-2026-63320)

    NOTE: https://gitlab.com/qemu-project/qemu/-/work_items/3607NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/4727cc883b7e81d2c30b9801af54482d65b84292 (v11.1.0-rc2)NOTE: Fixed by:
    https://gitlab.com/qemu-project/qemu/-/commit/95b9a1bf26fef7c44f4925f78ade7fa824ed5e76 (v11.0.4)     (CVE-2026-63322)

    NOTE: https://gitlab.com/qemu-project/qemu/-/work_items/3846NOTE: Fixed by: https://gitlab.com/qemu-     project/qemu/-/commit/370882d0869567e5f21b95229a763171e319d0db (v11.1.0-rc3)NOTE: Fixed by:
    https://gitlab.com/qemu-project/qemu/-/commit/e00b9c9193de00f5782cb919d91eb80d255017fe (v11.0.4)     (CVE-2026-65928)

    A flaw was found in QEMU. The VAPIC setup hypercall in hw/i386/vapic.c does not validate that the writable     RAM alias remains within the option ROM window. A privileged guest user on a Q35/KVM machine can position     this alias over locked SMRAM, bypassing chipset D_LCK protection and injecting code into System Management     Mode memory. (CVE-2026-81627)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - A flaw was found in QEMU. The VAPIC setup hypercall in hw/i386/vapic.c does not validate that the writable
    RAM alias remains within the option ROM window. A privileged guest user on a Q35/KVM machine can position
    this alias over locked SMRAM, bypassing chipset D_LCK protection and injecting code into System Management
    Mode memory. (CVE-2026-81627)

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - A flaw was found in QEMU. The VAPIC setup hypercall in hw/i386/vapic.c does not validate that the writable     RAM alias remains within the option ROM window. A privileged guest user on a Q35/KVM machine can position     this alias over locked SMRAM, bypassing chipset D_LCK protection and injecting code into System Management     Mode memory. (CVE-2026-81627)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
371849	Amazon Linux 2023 : qemu, qemu-common, qemu-guest-agent (ALAS2023-2026-3241)	Nessus	Amazon Linux Local Security Checks	Local	high
371765	Amazon Linux 2 : qemu (ALAS-2026-4009)	Nessus	Amazon Linux Local Security Checks	Local	high
473210	Echo: qemu: security update to 1:10.0.13+ds-0+deb13u1+e3	Tenable Cloud Security	Echo Local Security Checks	Local	high
473210	Echo: qemu: security update to 1:10.0.13+ds-0+deb13u1+e3	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
348219	Linux Distros Unpatched Vulnerability : CVE-2026-81627	Nessus	Misc.	Local	high

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